The present invention is in the field of energy harvesting techniques and relates to an energy harvesting system which may be useful in various applications including medical devices (e.g. implantable devices), as well as electric vehicles, and various domestic devices.
In the last two decades, the usage of electromagnetic communication, such as RF communication, has dramatically increased in all aspects of human life, including mobile/satellite communication, medical treatments, and the like, while different parts of the radio frequency spectrum can be used for different radio transmission technologies and applications (e.g., as TV (television) or cellular applications). Generally, the radio frequency spectrum is shared by civil, government, and military users of all nations, according to International Telecommunications Union (ITU) radio regulations. Thus, people all over the world are surrounded by a variety of electromagnetic signals (radiation), which propagate in the air and have different frequencies and strength.
There have been several attempts in the art to collect electromagnetic signals which propagate in the air, and to generate electrical power. Some techniques of the kind specified are described for example in the following patents: EP 1,722,284, US 2009/105,782, and JP 10146077.
In recent years, there has been a rapid technological advance in medical implanted and attached devices. However, the majority of these devices, if not all, require electricity as their energy source. Each such medical device uses batteries as a disposable electricity source. When it comes to implanted devices such as a heart pace maker or a defibrillator, a change of a battery per se requires repetitive surgeries that endanger the patient and expose him to various risks along with the fears before a surgery, inconvenient of the procedure, and recovery period that comes after. When it comes to attached devices such as a hearing aid, the change of batteries that may vary from once a day to once a week according to the device type is merely a nuisance.
Thus, it is obvious that a mechanism, capable of charging a battery and possibly eliminating a need for battery in such devices, is desired.